The present invention relates to calibration means for use with an adjustable headlamp which is capable of indicating a desired predetermined setting as well as variations from said predetermined setting. The calibration means retain the indication of the settings so that when the headlamp becomes misaligned, the headlamp can be readjusted to the desired predetermined setting.
Headlamp assemblies for vehicles, and more particularly, automobiles, have been studied, engineered, and designed to be less expensive and more aerodynamically efficient. In terms of aerodynamic efficiency, since a headlamp is positioned at the front of a vehicle wind drag on the vehicle can be affected by the shape of the headlamp. As such, headlamps have been aerodynamically designed to reduce the wind drag on the vehicle. Aerodynamic headlamp designs have resulted in sealed headlamp assemblies whereby each headlamp assembly includes a housing which is a sealed unit containing an adjustable reflector and an illuminating device or bulb mounted to the reflector.
Another design change that has been evolving in the automotive industry is the reduction of the overall vehicle size and the more efficient utilization of the space within the vehicle. Space within the engine compartment of the vehicle is utilized under close scrutiny in order to maximize the efficient use of the limited amount of space.
The sealed housing headlamp assemblies extend into the engine compartment. As previously mentioned, the reflector is adjustably retained within the housing of the headlamp assembly. Devices have been developed which are mounted to and extend through the housing and cooperate with the reflector to remotely adjust the horizontal and vertical orientation of the reflector. In this regard, each headlamp assembly typically uses a vertical and horizontal adjusting mechanism to adjust the reflector.
Several U.S. patents are listed below to provide examples of sealed housing headlamp assemblies including vertical and horizontal adjustment devices.
U.S. Pat. No. 5,067,052, Nov. 19, 1991 to Suzuki et al.;
U.S. Pat. No. 5,077,642, Dec. 31, 1991 to Lisak;
U.S. Pat. No. 5,121,303, Jun. 9, 1992 to Shirai et al.;
U.S. Pat. No. 5,140,503, Aug. 18, 1992 to Lisak.
The disclosures of the above patents are incorporated herein by reference and teach devices which include a single pivot point attached between the reflector and the housing. The pivot point provides a fixed reference from which the vertical and horizontal aiming adjustments are made. When a headlamp assembly is manufactured and installed into an automobile, each headlamp is photometrically aimed to comply with standard manufacturing and government specifications. The specifications dictate the horizontal and vertical positioning for a specific type of headlamp used in a specific type of automobile.
An additional problem which arises with sealed headlamp assemblies is the degree of ease and efficiency with which the assembly can be readjusted should it fall out of the specified adjustments. A headlamp may become misaligned as a result of the action of road vibrations on the assembly and adjusting devices or through collisions. Ordinarily, the vehicle would have to be brought to a facility such as a dealership, service station or garage to position the vehicle in front of an appropriate aiming grid to readjust the headlamp assembly to the appropriate specifications.
One solution to this problem was to provide zero adjustment calibration means mounted on the headlamp assembly which are set to indicate the initial specified adjustment. In this regard, these calibration assemblies are fixed to a stationary reference such as the housing and include indicia that indicate the initial desired adjustment position of the headlamp. Since the calibration assembly is adjusted relative to a fixed reference, should the reflector fall out of adjustment, the adjustment devices can be used to bring the indices into alignment thus readjusting the reflector to realign the headlamp. As a result, the vehicle headlamps can be adjusted quickly and easily without having to reaim the headlights against a reference aiming grid.
A variety of calibration assemblies have been developed and several are shown in the patent references cited above. For example, with regard to a vertical adjustment, the devices shown in Lisak '503 and Shirai '303 show a spirit level device attached to the reflector to indicate a desired vertical aiming adjustment. When the reflector is initially vertically adjusted, the spirit level attached thereto is adjusted so that a spirit on the level is centered or indicates a "zero adjustment." Should the reflector fall out of adjustment, the vertical aiming device can be operated to adjust the vertical aim of the reflector so that the spirit will once again read the "zero adjustment."
Calibration means have also been devised for the horizontal adjustment as shown in Shirai '303, Lisak '642, and Suzuki. These patents illustrate a plunger which is used to indicate the initial desired horizontal adjustment. In a similar manner to the vertical calibration assembly, the reflector is horizontally adjusted using photometric means at the factory to attain a desired position. The horizontal calibration assembly is then employed or operated to align certain indicia so that indicia associated with the plunger and a stationary component of the headlamp are aligned to include the "zero position" or desired horizontal orientation. If the reflector moves out of adjustment, the horizontal device will indicate such and the horizontal adjusting device can be used to adjust the reflector so that the horizontal calibration device once again reads the zero adjustment.
With the foregoing background information in mind, the problem has arisen regarding the cost and efficiency of the horizontal and vertical calibration assemblies of the prior art. The vertical and horizontal calibration assemblies discussed hereinabove effectively comprise two independent assemblies positioned generally proximate to the corresponding adjustment device. In other words, the vertical calibration assembly will be positioned near the vertical adjustment device, and the horizontal calibration assembly will be positioned near the horizontal adjustment device.
As previously mentioned, it is desirable to maximize the efficient utilization of space within the engine compartment, and as always to receive overall cost. By having two separate calibration assemblies at two independent locations for each headlamp, special structural and spatial considerations and clear view areas must be provided. As such, it is desirable to consolidate the vertical and horizontal calibration assembly into a single assembly area for each headlamp.
Additionally, it would be desirable to provide more economical calibration assemblies for use with headlamp assemblies. In this regard, the references presented hereinabove, utilized two independent calibration assemblies each having multiple components. The number of components, require that independent research and development for each component as well as manufacturing, part number accounting, and component accounting. Furthermore, the independent calibration assemblies impose structural requirements on the housing such that mountings must be provided for each calibration assembly thereby increasing the complexity of the molds and adding additional elements to the quality control reviews. Therefore, it would be desirable to provide a headlamp calibration assembly which minimizes the number of components used in the assembly to increase the economical efficiency of such an assembly.